Liquid crystal panel and electronic apparatus

ABSTRACT

A liquid crystal panel includes: first and second substrates arranged to be opposite each other at a predetermined gap; a liquid crystal layer filled between the first and second substrates; alignment films; a counter electrode pattern formed on the first substrate; and a pixel electrode pattern formed on the first substrate so as to have a plurality of electrode branches, the pixel electrode pattern having a partial connection branch formed around a contact so as to transversely connect a plurality of electrode branches extending from the contact from among the plurality of electrode branches.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 14/919,047, filed on Oct. 21, 2015, whichapplication is a continuation application of U.S. patent applicationSer. No. 12/642,312, filed on Dec. 18, 2009, issued as U.S. Pat. No.9,195,102 on Nov. 24, 2015, which application claims priority to JP2008-324779 filed in the Japan Patent Office on Dec. 19, 2008, theentire contents of which is hereby incorporated by reference.

BACKGROUND

The present application relates to a transverse electric field drivingliquid crystal panel which performs rotation control of the arrangementof liquid crystal molecules in parallel to a substrate surface by atransverse electric field generated between a pixel electrode and acounter electrode. The present application also relates to an electronicapparatus having the liquid crystal panel mounted therein.

At present, liquid crystal panels have various panel structurescorresponding to various driving methods including a vertical electricfield display type in which an electric field is generated in thevertical direction with respect to the panel surface. For example, atransverse electric field display type panel structure is suggested inwhich an electric field is generated in the horizontal direction withrespect to the panel surface.

In the transverse electric field display type liquid crystal panel, therotation direction of liquid crystal molecules is parallel to thesubstrate surface. That is, in the transverse electric field displaytype liquid crystal panel, there is little rotation of the liquidcrystal molecules in the vertical direction with respect to thesubstrate surface. For this reason, changes in the opticalcharacteristics (contrast, luminance, and color tone) are comparativelysmall. That is, the transverse electric field display type liquidcrystal panel has a wider viewing angle than the vertical electric fielddisplay type liquid crystal panel.

FIG. 1 shows an example of the sectional structure of a pixel regionconstituting a transverse electric field display type liquid crystalpanel. FIG. 2 shows an example of the corresponding planar structure.

A liquid crystal panel 1 has two glass substrates 3 and 5, and a liquidcrystal layer 7 filled so as to be sandwiched with the glass substrates3 and 5. A polarizing plate 9 is disposed on the outer surface of eachsubstrate, and an alignment film 11 is disposed on the inner surface ofeach substrate. Note that the alignment film 11 is used to arrange agroup of liquid crystal molecules of the liquid crystal layer 7 in apredetermined direction. In general, a polyimide film is used.

On the glass substrate 5, a pixel electrode 13 and a counter electrode15 are formed of a transparent conductive film. Of these, the pixelelectrode 13 is structured such that both ends of five comb-shapedelectrode branches 13A are respectively connected by connection portions13B. At the upper end of the pixel electrode 13 in FIG. 2, a rectangularcontact portion 13C is formed so as to be connected integrally to partof the electrode branches 13A and the connection portion 13B.

Meanwhile, the counter electrode 15 is formed below the electrodebranches 13A (near the glass substrate 5) so as to cover the entirepixel region. This electrode structure causes a parabolic electric fieldbetween the electrode branches 13A and the counter electrode 15. In FIG.1, this electric field is indicated by a dotted-line arrow.

The pixel region corresponds to a region surrounded by signal lines 21and scanning lines 23 shown in FIG. 2. In each pixel region, a thin filmtransistor for controlling the application of a signal potential to thepixel electrode 13 is disposed. The gate electrode of the thin filmtransistor is connected to a scanning line 23, so the thin filmtransistor is turned on/off by the potential of the scanning line 23.

One main electrode of the thin film transistor is connected to a signalline 21 through an interconnect pattern (not shown), and the other mainelectrode of the thin film transistor is connected to a contact 25.Thus, when the thin film transistor is turned on, the signal line 21 andthe pixel electrode 13 are electrically connected to each other.

As shown in FIG. 2, in this specification, a gap between the electrodebranches 13A is called a slit 31. In FIG. 2, the extension direction ofthe slit 31 is identical to the extension direction of the signal line21. That is, the slit 31 is formed along the Y-axis direction of FIG. 2.

For reference, FIGS. 3A and 3B show the sectional structure around thecontact 25.

JP-A-10-123482 and JP-A-11-202356 are examples of the related art.

SUMMARY

In the transverse electric field display type liquid crystal panel, itis known that, as shown in FIG. 4, the alignment of the liquid crystalmolecules is likely to be disturbed at both ends of the slit 31 (aroundthe connection portion of the electrode branches 13A and the connectionportion 13B or the contact 13C). This is because the contact portionserves as a rectangular electrode, so no transverse electric field isgenerated and weak alignment control is performed. Further, the portionaround the contact is quite uneven, so this portion causes disturbanceof alignment. This phenomenon is called disclination.

In FIG. 4, regions 41 where the above-described disclination is likelyto occur are shaded. In FIG. 4, the alignment of the liquid crystalmolecules is disturbed at eight regions 41 in total.

If external pressure (finger press or the like) is applied to thedisclination, as indicated by an arrow in the drawing, the disturbanceof the arrangement of the liquid crystal molecules is expanded along theextension direction of the electrode branches 13A. Note that thedisturbance of the arrangement of the liquid crystal molecules isapplied such that the arrangement of the liquid crystal molecules isrotated in a direction opposite to the electric field direction. Thisphenomenon is called a reverse twist phenomenon.

FIG. 5 shows an example of the occurrence of a reverse twist phenomenon.In FIG. 5, regions 43 where the arrangement of the liquid crystalmolecules is disturbed are shaded. These regions extend along theextension direction of the electrode branches 13A.

In the case of the liquid crystal panel being used at present, if thereverse twist phenomenon occurs, the original state is not restoredafter it has been left uncontrolled. This is because the disclinationexpanded from the upper portion of the pixel is linked with thedisclination expanded from the lower portion of the pixel at the centralportion of the pixel to form a stabilized state, and the alignmentdirection of the liquid crystal molecules in the regions 43 is notrestored to the original state. As a result, the regions 43 where thereverse twist phenomenon occurs may be continuously viewed as residualimages (that is, display irregularity). Hereinafter, the residual imageis called a reverse twist line.

Accordingly, a reverse twist line is likely to remain in two electrodebranches 13A directly extending from the contact portion 13C. In FIG. 5,two reverse twist lines at the central portion of the pixel region areemphasized over reverse twist lines on both sides.

An embodiment provides a liquid crystal panel. The liquid crystal panelincludes first and second substrates arranged to be opposite each otherat a predetermined gap, a liquid crystal layer filled between the firstand second substrates, alignment films, a counter electrode patternformed on the first substrate, and a pixel electrode pattern formed onthe first substrate so as to have a plurality of electrode branches, thepixel electrode pattern having a partial connection branch formed arounda contact so as to transversely connect a plurality of electrodebranches extending from the contact from among the plurality ofelectrode branches.

The pixel electrode pattern and the counter electrode pattern may beformed on the same layer surface, or may be formed on different layersurfaces. That is, if the liquid crystal panel is a transverse electricfield display type liquid crystal panel, and the pixel electrode has aslit, the sectional structure of the pixel region is not limited.

The cross angle between the extension direction of each slit formed bythe plurality of electrode branches constituting the pixel electrodepattern and the alignment direction of liquid crystal may be equal to orlarger than 7°.

As described above, the partial connection branch is formed in theregion around the contact with weak alignment stability so as totransversely connect a plurality of electrode branches. Therefore, eventhough liquid crystal is pressed down by external pressure, disclinationwhich occurs in the region around the contact can be prevented fromgrowing toward the center of the pixel along the electrode branches soas to be confined between the region around the contact and the partialconnection branch. As a result, the occurrence of display irregularity(reverse twist line) due to external pressure can be minimized.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram illustrating an example of the sectional structureof a transverse electric field display type liquid crystal panel.

FIG. 2 is a diagram illustrating an example of the planar structure of atransverse electric field display type liquid crystal panel.

FIGS. 3A and 3B are diagrams showing an example of the sectionalstructure around a contact.

FIG. 4 is a diagram illustrating disclination.

FIG. 5 is a diagram illustrating a reverse twist phenomenon.

FIG. 6 is a diagram showing an appearance example of a liquid crystalpanel module.

FIG. 7 is a diagram showing an example of the system configuration of aliquid crystal panel module.

FIG. 8 is a diagram showing a first pixel structure example (planarstructure).

FIG. 9 is a diagram illustrating an occurrence example of a reversetwist line.

FIG. 10 is a diagram showing a second pixel structure example (planarstructure).

FIG. 11 is a diagram illustrating the relationship between the magnitudeof a cross angle and display irregularity disappearance time.

FIG. 12 is a diagram illustrating the relationship between the magnitudeof a cross angle and the level of display irregularity.

FIG. 13 is a diagram illustrating the relationship between the magnitudeof a cross angle and relative transmittance.

FIG. 14 is a diagram showing a third pixel structure example (planarstructure).

FIG. 15 is a diagram showing a fourth pixel structure example (planarstructure).

FIG. 16 is a diagram showing a fifth pixel structure example (sectionalstructure).

FIG. 17 is a diagram showing a sixth pixel structure example (sectionalstructure).

FIG. 18 is a diagram showing the sixth pixel structure example (planarstructure).

FIG. 19 is a diagram showing a seventh pixel structure example (planarstructure).

FIG. 20 is a diagram illustrating the system configuration of anelectronic apparatus.

FIG. 21 is a diagram showing an appearance example of an electronicapparatus.

FIGS. 22A and 22B are diagrams showing an appearance example of anelectronic apparatus.

FIG. 23 is a diagram showing an appearance example of an electronicapparatus.

FIGS. 24A and 24B are diagrams showing an appearance example of anelectronic apparatus.

FIG. 25 is a diagram showing an appearance example of an electronicapparatus.

DETAILED DESCRIPTION

The present application will be described as follows with reference tothe drawings according to an embodiment.

(A) Appearance Example of Liquid Crystal Panel Module and PanelStructure

(B) Pixel Structure Example 1: Single Domain Structure

(C) Pixel Structure Example 2: Pseudo Dual Domain Structure

(D) Pixel Structure Example 3: Dual Domain Structure

(E) Pixel Structure Example 4: Dual Domain Structure

(F) Pixel Structure Example 5: Different Sectional Structure

(G) Pixel Structure Example 6: Different Sectional Structure

(H) Pixel Structure Example 7: Different Pixel Structure Example

(I) Other Examples

Elements which are not provided with particular drawings or descriptionsherein are realized by existing techniques in the relevant technicalfield. Embodiments described below are only exemplary, and theapplication is not limited thereto.

(A) Appearance Example of Liquid Crystal Panel Module and PanelStructure

FIG. 6 shows an appearance example of a liquid crystal panel module 51.The liquid crystal panel module 51 is structured such that a countersubstrate 55 is bonded to a support substrate 53. The support substrate53 is made of glass, plastic, or other substrates. The counter substrate55 is also made of glass, plastic, or other transparent substrates. Thecounter substrate 55 is a member which seals the surface of the supportsubstrate 53 with a sealant interposed therebetween.

Note that only one substrate on the light emission side may be atransparent substrate, and the other substrate may be a nontransparentsubstrate.

Further, the liquid crystal panel 51 is provided with an FPC (FlexiblePrinted Circuit) 57 for inputting an external signal or driving power,if necessary.

FIG. 7 shows an example of the system configuration of the liquidcrystal panel module 51. The liquid crystal panel module 51 isconfigured such that a pixel array section 63, a signal line driver 65,a gate line driver 67, and a timing controller 69 are disposed on alower glass substrate 61 (corresponding to the glass substrate 5 of FIG.1). In this embodiment, the driving circuit of the pixel array section63 is formed as a single or a plurality of semiconductor integratedcircuits, and is mounted on the glass substrate.

The pixel array section 63 has a matrix structure in which white unitseach constituting one pixel for display are arranged in M rows×Ncolumns. In this specification, the row refers to a pixel row of 3×Nsubpixels 71 arranged in the X direction of the drawing. The columnrefers to a pixel column of M subpixels 71 arranged in the Y directionof the drawing. Of course, the values M and N are determined dependingon the display resolution in the vertical direction and the displayresolution in the horizontal direction.

The signal line driver 65 is used to apply a signal potential Vsigcorresponding to a pixel gradation value to signal lines DL. In thisembodiment, the signal lines DL are arranged so as to extend in the Ydirection of the drawing.

The gate line driver 67 is used to apply control pulses for providingthe write timing of the signal potential Vsig to scanning lines WL. Inthis embodiment, the scanning lines WL are arranged so as to extend inthe X direction of the drawing.

A thin film transistor (not shown) is formed in each subpixel 71. Thethin film transistor has a gate electrode connected to a correspondingone of the scanning lines WL, one main electrode connected to acorresponding one of the signal lines DL, and the other main electrodeconnected to the pixel electrode 13.

The timing controller 69 is a circuit device which supplies drivingpulses to the signal line driver 65 and the gate line driver 67.

(B) Pixel Structure Example 1

FIG. 8 shows a pixel structure example. This pixel structure is used inan FFS (Fringe Field Switching) type liquid crystal panel.

Thus, the sectional structure of the pixel region is the same as shownin FIG. 1. That is, the counter electrode 15 is disposed below the pixelelectrode 13 so as to cover the entire pixel region.

The pixel structure shown in FIG. 8 has the same basic structure as thepixel structure shown in FIG. 2. That is, the pixel electrode 13 isstructured such that both ends of comb-shaped five electrode branches13A are respectively connected to each other by connection portions 13B.

The pixel electrode 13 has a contact portion 13C at the upper end of thepixel region in the drawing. The contact portion 13C is connected to thethin film transistor (not shown) through a contact 25 formed at thecentral portion thereof.

One end of the contact portion 13C is connected to the connectionportion 13B, and the other end of the contact portion 13C is connectedto three electrode branches 13A.

The three electrode branches 13A are electrode branches 13A other thantwo electrode branches 13A at both ends from among the five electrodebranches 13A.

The contact portion 13C has a large pattern area. For this reason, atthe boundary between the contact portion 13C and two slits 31 which areformed by the three electrode branches 13A directly connected to thecontact portion 13C, alignment stability is likely to be weakened. Theweak alignment stability means that reverse twist which occurs whenliquid crystal is pressed down is likely to grow.

Accordingly, in the pixel structure example of FIG. 8, a partialconnection branch 81 is formed around the contact portion 13C so as totransversely connect the three electrode branches 13A directly extendingfrom the contact portion 13C. With this partial connection portion 81,the two slits 31 formed by the three electrode branches 13A at thecentral portion of the pixel region can be physically divided into tworegions.

The two slits 31 are slits where the growth of reverse twist is likelyto dominantly appear when liquid crystal is pressed down.

However, with the partial connection branch 81, even though liquidcrystal is pressed down, the growth of the reverse twist can be confinedwithin the slit 31 on the contact portion 13C side and can be preventedfrom reaching around the center of the pixel region. FIG. 9 shows astate where liquid crystal is pressed down due to external pressure.

As will be understood from the comparison of FIGS. 9 and 5, in the pixelregion where the partial connection branch 81 is formed, a reverse twistline which remains in the pixel region is significantly reduced. Inparticular, a reverse twist line which occurs around the center of thepixel region can be eliminated or significantly reduced.

As a result, with this pixel structure, the display quality can besignificantly improved over the liquid crystal panel.

It is preferable that the space formed between the contact portion 13Cand the partial connection branch 81 is as small as possible. Forexample, the space is preferably small to be close to the manufacturinglimit. This is because, the narrower the space, the more the area of thepixel region to which the alignment regulation force is applied can beincreased.

Similarly, it should suffice that the partial connection branch 81 candivide the region into two parts, so the pattern width of the partialconnection branch 81 is preferably thin to be close to the manufacturinglimit.

(C) Pixel Structure Example 2

FIG. 10 shows a second pixel structure example. It is assumed that thispixel structure example is also used in an FFS (Fringe Field Switching)type liquid crystal panel.

The pixel electrode 13 has the same basic pattern structure as theabove-described pixel structure example (FIG. 8). That is, the pixelelectrode 13 has five electrode branches 13A, a connection portion 13B,a contact portion 13C, and a partial connection branch 81.

Meanwhile, in the above-described pixel structure example (FIG. 8), thecase where the signal lines 21 and the electrode branches 13A are formedin parallel to the Y-axis direction has been described.

The pixel structure example of FIG. 10 is different from theabove-described pixel structure example in that the wirings in the pixelregion are formed so as to be inclined with respect to the Y-axisdirection.

The inclination direction is inverted between two upper and lower pixelregions arranged in the Y-axis direction. That is, a pattern which isinclined in the clockwise direction with respect to the Y-axis directionand a pattern which is inclined in the counterclockwise direction withrespect to the Y-axis direction are alternately disposed along theY-axis direction. In other words, the pixel regions in this embodimenthave a vertical mirror structure with respect to the scanning line 23extending in the X-axis direction.

FIG. 10 mainly shows a case where the pattern of the pixel region isinclined in the clockwise direction with respect to the Y-axisdirection. The alignment direction of the alignment film 11 is parallelto the Y-axis direction. Therefore, in this pixel region, the liquidcrystal molecules rotate in the counterclockwise direction by theapplication of an electric field.

Of course, a pixel region where the pattern in the pixel region isinclined in the counterclockwise direction with respect to the Y-axisdirection is formed above and below the pixel region shown in FIG. 10.In this region, the liquid crystal molecules rotate in the clockwisedirection by the application of an electric field.

As described above, the rotation direction of the liquid crystalmolecules is inverted between the two upper and lower pixel regions, soa liquid crystal panel with a wide viewing angle can be realized.

The above-described pixel structure constitutes a pseudo dual domainstructure.

Hereinafter, the preferable relationship between the alignment directionof the liquid crystal layer 7 and the extension direction of each slit31 formed by the electrode branches 13A will be described. Note that thealignment direction of the liquid crystal layer 7 (also referred to as“alignment direction of liquid crystal”) is defined by the orientationof dielectric anisotropy of liquid crystal, and refers to a directionwith a large dielectric constant.

In the pixel structure of FIG. 10, a case where the cross angle αbetween the alignment direction of the liquid crystal layer 7 and theextension direction of each slit 31 formed by the electrode branches 13Ais equal to or larger than 7° is shown as a preferred structure.

This value is determined by the following experiment. Hereinafter, thecharacteristics confirmed by the inventors will be described.

FIG. 11 shows the characteristics which are recognized between theextension direction of the slit 31 and the alignment direction of theliquid crystal layer 7. FIG. 11 shows the relationship between the crossangle α and the time until display irregularity disappears. In FIG. 11,the horizontal axis denotes the cross angle α between the extensiondirection of the slit 31 and the alignment direction of the liquidcrystal layer 7, and the vertical axis denotes the time until displayirregularity disappears.

From the experiment result shown in FIG. 11, when the cross angle α issmaller than 7°, it has been confirmed that display irregularity due tothe reverse twist phenomenon does not disappear by itself.

Meanwhile, when the cross angle α is equal to or larger than 7°, it hasbeen confirmed that display irregularity due to the reverse twistphenomenon can disappear by itself. For this reason, in FIG. 10, thecross angle α is shown to be equal to or larger than 7°.

When the cross angle α is 7°, the time until display irregularitydisappears is 3.5 [seconds]. The experiment shows that, as the crossangle α becomes larger, the time until display irregularity disappearsis shortened.

For example, when the cross angle α is 10°, it has been confirmed thatdisplay irregularity disappears in 3 [seconds]. When the cross angle αis 15°, it has been confirmed that display irregularity disappears in2.5 [seconds]. When the cross angle α is 20°, it has been confirmed thatdisplay irregularity disappears in 1.5 [seconds].

From this, it can be seen that, as the cross angle α becomes larger, thealignment regulation force of the liquid crystal molecules in thetransverse electric field display type liquid crystal panel can beincreased.

FIG. 12 shows the observation result regarding the relationship betweenthe cross angle α and the level of display irregularity. In FIG. 12, thehorizontal axis denotes the cross angle α between the extensiondirection of the slit 31 and the alignment direction of the liquidcrystal layer 7, and the vertical axis denotes the visible level ofdisplay irregularity.

As shown in FIG. 12, if the cross angle α is equal to or larger than10°, it has been confirmed that no display irregularity is observed evenwhen the display screen is viewed at any angle. When the cross angle αis 5°, it has been confirmed that, when the display screen is viewedfrom an oblique direction, slight display irregularity is observed. Whenthe cross angle α is equal to or larger than 5° and smaller than 10°, asshown in FIG. 12, it has been confirmed that visibility is graduallychanged.

However, the larger cross angle α is not necessarily the better.

FIG. 13 shows the confirmed transmission characteristics. In FIG. 13,the horizontal axis denotes the cross angle α between the extensiondirection of the slit 31 and the alignment direction of the liquidcrystal layer 7, and the vertical axis denotes relative transmittance.In FIG. 13, it is assumed that, when the cross angle α is 5°, therelative transmittance is 100%.

In FIG. 13, when the cross angle α is 5°, the maximum transmittance isobtained, and when the cross angle α is 45°, the minimum transmittanceis obtained. Note that, when the cross α is 45°, the relativetransmittance is about 64%.

As shown in FIG. 13, it has been seen that the cross angle α and therelative transmittance have a roughly linear relationship. From theviewpoint of transmittance, it can be seen that, as the cross angle α issmaller, better display luminance is obtained.

From the above-described characteristics, the inventors have consideredit preferable that the cross angle α between the extension direction ofthe slit 31 and the alignment direction of the liquid crystal layer 7 beequal to or larger than 7° and equal to or smaller than 15°. If thiscondition is satisfied, the relative transmittance and the time untildisplay irregularity disappears can be maintained appropriately.

Therefore, a liquid crystal panel can be realized in which, even thoughthe reverse twist phenomenon due to finger press or the like disturbsthe arrangement of the liquid crystal molecules, the disturbance can beeliminated by itself in several seconds.

(D) Pixel Structure Example 3

FIG. 14 shows a third pixel structure example. This pixel structure isalso used in an FFS (Fringe Field Switching) type liquid crystal panel.

However, in the third pixel structure, each pixel region has a dualdomain structure. That is, the pixel electrode 13 is bent around thecenter of the pixel region (in the drawing, a rectangular regionindicated by a broken line) in the Y-axis direction.

In FIG. 14, one bend point is provided, but two or more bend points maybe provided to form a multi-domain structure.

The pixel structure shown in FIG. 14 has a vertical mirror structurealong a virtual line extending along the X-axis direction from the bendpoint. One contact portion 13C and one partial connection branch 81 areprovided in the pixel region. Therefore, the contact portion 13C andpartial connection branch 81 are not included in the vertical mirrorstructure. The vertical mirror structure includes the signal line 21 aswell as the pixel electrode 13.

Under this condition, the cross angle α between the alignment directionof the liquid crystal layer 7 and the extension direction of the slit 31is set to be equal to or larger than 7°. Of course, from the viewpointof display performance, it is preferable that the cross angle α is equalto or larger than 7° and smaller than 15°. Further, it is assumed thatthe alignment direction of the liquid crystal layer 7 is parallel to theY-axis direction.

In the case of the pixel structure with a dual domain structure, therotation direction of the liquid crystal molecules is inverted betweenthe upper half portion and the lower half portion of the pixel region.That is, while the liquid crystal molecules in the upper half portion ofthe pixel region of the drawing rotate in the counterclockwise directionby the application of an electric field, and the liquid crystalmolecules in the lower half portion of the pixel region of the drawingrotate in the clockwise direction by the application of an electricfield.

As described above, the rotation direction of the liquid crystalmolecules is inverted, so the amount of light per pixel can be madeuniform even when the display screen is viewed at any angle. Therefore,a liquid crystal panel with a wider viewing angle than the first pixelstructure can be realized.

Of course, as described above, the relationship between the alignmentdirection of the liquid crystal layer 7 and the extension direction ofthe slit 31 is optimized. Therefore, even though the reverse twist dueto finger press or the like disturbs the arrangement of the liquidcrystal molecules, the disturbance can be eliminated by itself inseveral seconds.

(E) Pixel Structure Example 4

FIG. 15 shows a fourth pixel structure example. This pixel structurecorresponds to a modification of the dual domain structure shown in FIG.14. That is, the pixel structure shown in FIG. 15 corresponds to a pixelstructure in which each pixel has a dual domain structure, and has thesame basic pixel structure as the pixel structure shown in FIG. 14.

A difference is that a connection branch 13D is additionally provided soas to transversely connect the bend points of the electrode branches 13Ato each other.

The reason is as follows. In the third pixel structure of FIG. 14, therotation direction of the liquid crystal molecules is inverted at theboundary between the domains (a portion around the bend point). For thisreason, the alignment regulation force is weakened at the boundary,which causes alignment disturbance. The alignment disturbance mayadversely affect the disappearance of the reverse twist line phenomenon.

Meanwhile, in the pixel structure example of FIG. 15, two domains can bephysically separated from each other by the connection branch 13C whichconnects all the five electrode branches 13A at the bend points.

For this reason, it is possible to eliminate disturbance of thearrangement of the liquid crystal molecules at the boundary between thedomains. As a result, with the pixel structure shown in FIG. 15, thetime until the reverse twist line disappears can be further shortened,as compared with the pixel structure shown in FIG. 14.

(F) Pixel Structure Example 5

In the above-described four pixel structure examples, the FFS typeliquid crystal panel having the sectional structure described withreference to FIG. 1 has been described. That is, a liquid crystal panelhas been described which has a pixel structure in which the counterelectrode 15 is disposed below the comb-shaped pixel electrode 13 so asto cover the entire pixel region.

Alternatively, as shown in FIG. 16, a liquid crystal panel 91 having acomb-shaped counter electrode 15 may be adopted. In FIG. 16, thecorresponding elements to those in FIG. 1 are represented by the samereference numerals.

In FIG. 16, the electrode branches 15A of the counter electrode 15 aredisposed so as to fill the spaces (slits 31) between the electrodebranches 13A of the pixel electrode 13.

That is, the electrode branches 15A of the counter electrode 15 aredisposed so as not to overlap the electrode branches 13A of the pixelelectrode 13 in the pixel region. Of course, there is no difference inthe electric field formed between the pixel electrode 13 and the counterelectrode 15.

(G) Pixel Structure Example 6

In the above-described pixel structure examples, the description hasbeen made of the pixel structure in which the pixel electrode 13 and thecounter electrode 15 are formed in different layers.

Alternatively, the technique which has been suggested by the inventorsmay also be applied to a transverse electric field display type liquidcrystal panel in which the pixel electrode 13 and the counter electrode15 are formed in the same layer.

FIG. 17 shows a sectional structure example corresponding to a sixthpixel structure example. FIG. 18 shows a planar structure examplecorresponding to the sixth pixel structure example. Note that the liquidcrystal panel has the same basic structure as the liquid crystal panelwith a different pixel structure.

That is, the liquid crystal panel 101 includes two glass substrates 3and 5, and a liquid crystal layer 7 filled so as to be sandwiched withthe glass substrates 3 and 5. A polarizing plate 9 is disposed on theouter surface of each substrate, and an alignment film 11 is disposed onthe inner surface of each substrate.

In the liquid crystal panel 101 of FIG. 17, the pixel electrode 13 andthe counter electrode 15 are formed on the glass substrate 5.

Of these, the pixel electrode 13 is structured such that one ends ofcomb-shaped four electrode branches 13A are connected to each other by aconnection portion 13B.

Meanwhile, the counter electrode 15 in the pixel region is comb-shaped,similarly to FIG. 16. In FIG. 17, three electrode branches 15A areformed in the pixel region, and one end of each electrode branch 15A isconnected to a common electrode line 33. In this case, the electrodebranches 15A of the counter electrode 15 are formed in the same layer asthe pixel electrode 13 so as to be fitted into the spaces between theelectrode branches 13A of the pixel electrode 13. The common electrodeline 33 is formed in a lattice shape so as to follow the signal lines 21and the scanning lines 23, as shown in FIG. 18.

As described above, in this pixel structure example, the electrodebranches 13A of the pixel electrode 13 and the electrode branches 15A ofthe counter electrode 15 are disposed in the same layer so as toalternately appear in the X-axis direction. With this electrodestructure, a parabolic electric field is generated between the electrodebranches 13A of the pixel electrode 13 and the electrode branches 15A ofthe counter electrode 15. In FIG. 17, this electric field is indicatedby a broken line.

As shown in FIG. 18, in this pixel structure example, two electrodebranches 13A directly extend from the contact portion 13C. Therefore, inthis pixel structure, a partial connection branch 81 is formed so as toconnect the two electrode branches 13A to each other.

With this pixel structure, a liquid crystal panel can be realized inwhich a reverse twist line is unlikely to occur around the center of thepixel region due to external pressure, such as finger press or the like.

(H) Pixel Structure Example 7

In the above-described six pixel structure examples, a case where theextension direction of each slit 31 formed by the electrode branches 13Aof the pixel electrode 13 is parallel to the Y-axis direction or crossesthe Y-axis direction at an acute angle has been described.

Alternatively, the extension direction of each slit 31 formed by theelectrode branches 13A of the pixel electrode 13 may be parallel to theX-axis direction or may cross the X-axis direction at an acute angle.

FIG. 19 shows an example of such a pixel structure. FIG. 19 shows apixel structure example when the pixel electrode 13 and the counterelectrode 15 are disposed in different layers on the glass substrate 5(FIG. 1). Of course, the same pixel structure as the sixth pixelstructure example may also be considered.

Description will be made again with reference to FIG. 19. In FIG. 19,the electrode branches 13A of the pixel electrode 13 are formed inparallel to the scanning line 23. Both ends of the electrode branches13A are connected by connection portions 13B. For this reason, a slit 31formed between the electrode branches 13A extends in the X direction.

In this pixel structure example, the alignment regulation force islikely to be weakened at the boundary between the contact portion 13Cand the electrode branch 13A directly extending from the contact portion13C.

However, the partial connection branch 81 is formed so as to transversethe electrode branches 13A, so, as in the above-described pixelstructure examples, a reverse twist line due to the application ofexternal pressure in the relevant region can be effectively preventedfrom growing.

(I) Other Examples

(I-1) Substrate Material

In the above description of the examples, the substrate is a glasssubstrate, but a plastic substrate or other substrates may be used.

(I-2) Alignment Direction 1 of Alignment Film

Of the above-described examples, in the case of the pixel structureexample 1 (FIG. 8), it is assumed that the alignment direction of theliquid crystal layer 7 and the extension direction of the slit 31 crosseach other at an acute angle of about 3°.

Of course, when the cross angle α is equal to or larger than 7°,similarly to the pixel structure example 2 (FIG. 10), the generatedreverse twist line can be eliminated when the liquid crystal panel isleft uncontrolled.

(I-3) Alignment Direction 1 of Alignment Film

Of the above-described examples, in the case of the pixel structureexample 2 (FIG. 10), the pixel structure example 3 (FIG. 14), and thepixel structure example 4 (FIG. 15), an example where the cross angle αformed between the alignment direction of the liquid crystal layer 7 andthe extension direction of the slit 31 is equal to or larger than 7° hasbeen described.

Alternatively, the cross angle α may be smaller than 7°. In this case,display irregularity remains, but as described with reference to FIG. 9,a reverse twist line can be effectively prevented from growing at thecentral portion of the pixel region, so display quality can be improved.

(I-4) Product Examples

In the above description, various pixel structures capable of generatinga transverse electric field have been described. Hereinafter,description will be provided for electronic apparatuses in which aliquid crystal panel having the pixel structure according to theexamples (with no driving circuit mounted therein) or a liquid crystalpanel module (with a driving circuit mounted therein) is mounted.

FIG. 20 shows a conceptual example of the configuration of an electronicapparatus 111. The electronic apparatus 111 includes a liquid crystalpanel 113 having the above-described pixel structure, a system controlunit 115, and an operation input unit 117. The nature of processingperformed by the system control unit 115 varies depending on the producttype of the electronic apparatus 111.

The configuration of the operation input unit 117 varies depending onthe product type. A GUI (Graphic User Interface), switches, buttons, apointing device, and other operators may be used as the operation inputunit 117.

It should be noted that the electronic apparatus 111 is not limited toan apparatus designed for use in a specific field insofar as it candisplay an image or video generated inside or input from the outside.

FIG. 21 shows an appearance example of a television receiver as anelectronic apparatus. A television receiver 121 has a display screen 127on the front surface of its housing. The display screen 127 includes afront panel 123, a filter glass 125, and the like. The display screen127 corresponds to the liquid crystal panel according to the embodiment.

The electronic apparatus 111 may be, for example, a digital camera.FIGS. 22A and 22B show an appearance example of a digital camera 131.FIG. 22A shows an appearance example as viewed from the front (from thesubject), and FIG. 22B shows an appearance example when viewed from therear (from the photographer).

The digital camera 131 includes a protective cover 133, an imaging lenssection 135, a display screen 137, a control switch 139, and a shutterbutton 141. Of these, the display screen 137 corresponds to the liquidcrystal panel according to the embodiment.

The electronic apparatus 111 may be, for example, a video camcorder.FIG. 23 shows an appearance example of a video camcorder 151.

The video camcorder 151 includes an imaging lens 155 provided to thefront of a main body 153 so as to capture the image of the subject, aphotographing start/stop switch 157, and a display screen 159. Of these,the display screen 159 corresponds to the liquid crystal panel accordingto the embodiment.

The electronic apparatus 111 may be, for example, a personal digitalassistant. FIGS. 24A and 24B show an appearance example of a mobilephone 161 as a personal digital assistant. The mobile phone 161 shown inFIGS. 24A and 24B is a folder type mobile phone. FIG. 24A shows anappearance example of the mobile phone in an unfolded state, and FIG.24B shows an appearance example of the mobile phone in a folded state.

The mobile phone 161 includes an upper housing 163, a lower housing 165,a connection portion (in this example, a hinge) 167, a display screen169, an auxiliary display screen 171, a picture light 173, and animaging lens 175. Of these, the display screen 169 and the auxiliarydisplay screen 171 correspond to the liquid crystal panel according tothe embodiment.

The electronic apparatus 111 may be, for example, a computer. FIG. 25shows an appearance example of a notebook computer 181.

The notebook computer 181 includes a lower housing 183, an upper housing185, a keyboard 187, and a display screen 189. Of these, the displayscreen 189 corresponds to the liquid crystal panel according to theembodiment.

In addition to the above-described electronic apparatuses, theelectronic apparatus 111 may be, for example, a projector, an audioplayer, a game machine, an electronic book, an electronic dictionary, orthe like.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope and without diminishing itsintended advantages. It is therefore intended that such changes andmodifications be covered by the appended claims.

The application is claimed as follows:
 1. A liquid crystal panel comprising: first and second substrates arranged to be opposite each other at a predetermined gap; a liquid crystal layer filled between the first and second substrates; a counter electrode pattern formed on the first substrate; a pixel electrode pattern formed on the first substrate; scanning lines to which control pulses for providing write timing of a signal potential are applied, the scanning lines extending in a first direction; and signal lines to which the signal potential is applied, wherein the pixel electrode pattern includes a contact portion connected to a first main electrode of a transistor, whose gate electrode is connected to one of the scanning lines, and whose second main electrode is connected to one of the signal lines, a plurality of elongated electrode branches having lengths greater than widths and formed in a pixel region surrounded by the scanning lines and signal lines, a plurality of elongated slits having lengths greater than widths and formed between the electrode branches in a lengthwise extending direction of the electrode branches, a partial connection branch of the pixel electrode pattern that is positioned nearer to the contact portion than to a center of the pixel region and that subdivides a plurality of the slits in the lengthwise extending direction of the electrode branches into a plurality of slit portions aligned in said lengthwise extending direction of the electrode branches, a first connection portion connecting ends of each of the electrode branches at ends adjacent to the contact portion, and a second connection portion connecting other ends of each of the electrode branches, wherein the electrode branches include: first electrode branches that connect the first connection portion and the second connection portion; and second electrode branches that connect the partial connection branch and the second connection portion, wherein the contact portion is arranged between the first electrode branches in a widthwise extending direction of the electrode branches, the slit portions of each of the slits include a first slit portion and a second slit portion that is shorter than the first slit portion, and the second slit is disposed between the contact portion and the partial connection branch, and wherein the partial connection branch is disposed between each of the first slit portion and the second slit portion of each of the slits, and wherein the pixel electrode pattern in the pixel region overlaps the scanning lines surrounding the pixel region.
 2. The electronic apparatus according to claim 1, wherein a center line of the partial connection branch and a center line of the pixel region extend along an extending direction of the elongated electrode branches.
 3. The electronic apparatus according to claim 1, wherein the contact portion is arranged between the first connection portion and the partial connection branch in the lengthwise extending direction of the electrode branches.
 4. A liquid crystal panel comprising: first and second substrates arranged to be opposite each other at a predetermined gap; a liquid crystal layer filled between the first and second substrates; a counter electrode pattern formed on the first substrate; a pixel electrode pattern formed on the first substrate; scanning lines to which control pulses for providing write timing of a signal potential are applied, the scanning lines extending in a first direction; and signal lines to which the signal potential is applied, wherein the pixel electrode pattern includes a contact portion connected to a first main electrode of a transistor, whose gate electrode is connected to one of the scanning lines, and whose second main electrode is connected to one of the signal lines, a plurality of elongated electrode branches having lengths greater than widths and formed in a pixel region surrounded by the scanning lines and signal lines, a plurality of elongated slits having lengths greater than widths and formed between the electrode branches in a lengthwise extending direction of the electrode branches, a partial connection branch of the pixel electrode pattern that is positioned nearer to the contact portion than to a center of the pixel region and that subdivides a plurality of the slits in the lengthwise extending direction of the electrode branches into a plurality of slit portions aligned in said lengthwise extending direction of the electrode branches, a first connection portion connecting ends of each of the electrode branches at ends adjacent to the contact portion, and a second connection portion connecting other ends of each of the electrode branches, wherein the electrode branches include: first electrode branches that connect the first connection portion and the second connection portion; and second electrode branches that connect the partial connection branch and the second connection portion, wherein the contact portion is arranged between the first electrode branches in a widthwise extending direction of the electrode branches, wherein the slit portions of each of the slits include a first slit portion and a second slit portion that is shorter than the first slit portion, and the second slit portion is disposed between the contact portion and the partial connection branch, wherein the partial connection branch is disposed between each of the first slit portion and the second slit portion of each of the slits, and wherein one of the slits is arranged between the contact portion and one of the signal lines in the first direction.
 5. The liquid crystal panel according to claim 4, wherein the pixel electrode pattern and the counter electrode pattern are formed on the same layer surface.
 6. The liquid crystal panel according to claim 4, wherein the pixel electrode pattern and the counter electrode pattern are formed on different layer surfaces.
 7. The liquid crystal panel according to claim 5, wherein the cross angle between the extension direction of each slit formed by the plurality of electrode branches constituting the pixel electrode pattern and an alignment direction of liquid crystal is equal to or larger than 7°.
 8. The liquid crystal panel according to claim 4, wherein a center line of the partial connection branch and a center line of the pixel region extend along an extending direction of the elongated electrode branches.
 9. The liquid crystal panel according to claim 4, wherein the contact portion is arranged between the first connection portion and the partial connection branch in the lengthwise extending direction of the electrode branches.
 10. The liquid crystal panel according to claim 6, wherein the cross angle between the extension direction of each slit formed by the plurality of electrode branches constituting the pixel electrode pattern and an alignment direction of liquid crystal is equal to or larger than 7°.
 11. The liquid crystal panel according to claim 1, wherein the first slit portion and the second slit portion are aligned in the lengthwise extending direction of the electrode branches.
 12. The liquid crystal panel according to claim 4, wherein the first slit portion and the second slit portion are aligned in the lengthwise extending direction of the electrode branches.
 13. The liquid crystal panel according to claim 1, wherein the pixel electrode pattern is lengthwise in a pattern lengthwise direction based on an overall shape of the pixel electrode pattern, and wherein the first slit portion and the second slit portion are aligned in the lengthwise extending direction of the electrode branches and aligned in the pattern lengthwise direction.
 14. The liquid crystal panel according to claim 4, wherein the pixel electrode pattern is lengthwise in a pattern lengthwise direction based on an overall shape of the pixel electrode pattern, and wherein the first slit portion and the second slit portion are aligned in the lengthwise extending direction of the electrode branches and aligned in the pattern lengthwise direction. 